Conjure Animals can be upgraded by spending spell slots of level 5, 7
and 9, where Summon Lesser Demons is upgraded by spending spell slots
of levels 6 and 8, and has no equivalent to CA's final spell slot
upgrade.

When given the option to cast either spell, why would someone cast Summon Lesser Demons?

\$\begingroup\$What are you using as your metric to compare? What are you trying to do with the summoned creatures? Or are you just asking what the purpose of Summon Lesser Demons is and not trying to do a comparison?\$\endgroup\$
– NautArchFeb 7 at 17:20

1

\$\begingroup\$@NautArch Any available method. If there is value in demons as a creature type, or demons have a particular trend in their statblocks that may prove useful that beasts don't, or any variant thereof. In terms of CR, spell slot spent, or the RAW of the spell, SLD is equal or worse, so in what scenario would I prefer SLD?\$\endgroup\$
– Daniel ZastoupilFeb 7 at 17:52

\$\begingroup\$How would you be "given the option to cast either spell"? They're for different classes.\$\endgroup\$
– Mark WellsFeb 7 at 22:16

\$\begingroup\$@MarkWells Multiclassing, scrolls, staves, or perhaps creating an NPC statblock. A level 10 character with 5 Druid and 5 Wizard might not be the most optimized but it's definitely plausible.\$\endgroup\$
– Daniel ZastoupilFeb 7 at 22:56

2 Answers
2

Summoning demons might be more useful than conjuring animals depending on the circumstances and desired results. For instance...

Demons are immune to poison

One trait that all demons have in common is that they are immune to poison damage and the poisoned condition. If you are fighting against enemies which rely on poison damage and status effects, they will have a harder time against a bunch of demons than against a bunch of mundane beasts.

Demons are inherently scarier and do weird things

For the common person, hostile wild animals are certainly scary, but hostile demons are undoubtedly more so; and where animals will simply physically attack their foes, demons tend to have extra magical or unusual abilities which make them more versatile. If your goal is to create as much fear and chaos as possible, a squad of demons will do that job more effectively than a gaggle of beasts, even if, according to game statistics, they're actually equivalently dangerous. Where town guards might be confident enough to take on a boar or bear, they might flee in terror at the sight of a demon... even lesser ones.

It also provides the DM a convenient character option for villains to use, since summoning literal demons is a good way to paint an antagonist as obviously evil.

\$\begingroup\$Demons often also have speech, intelligence, and thumbs, a big help in actually doing things. I can summon a demon to work on my taxes, try that with a squirrel.\$\endgroup\$
– JohnFeb 7 at 20:31

2

\$\begingroup\$@John the demons summoned by the spell, though, are explicitly hostile to all creatures, including the caster; they only won't attack you if you stay within a circle of blood you create at the time of casting.\$\endgroup\$
– CarcerFeb 7 at 20:37

5

\$\begingroup\$@John have you ever seen a squirrel try to do taxes? It's nuts.\$\endgroup\$
– RubiksmooseFeb 7 at 20:37

1

\$\begingroup\$@John ... and the animals summoned by Conjure Animals are actually fey spirits in the form of animals, and follow your verbal instructions...\$\endgroup\$
– CarcerFeb 7 at 20:50

\$\begingroup\$Note that the material component can be replaced by a component pouch.\$\endgroup\$
– RubiksmooseFeb 7 at 20:28

\$\begingroup\$@Rubiksmoose RAW yes, but I have not met a DM who allowed that.\$\endgroup\$
– AndrásFeb 7 at 20:29

\$\begingroup\$You may also want to consider this from the perspective of a DM. PCs are not the only ones to use spells and often spells have different uses for DMs.\$\endgroup\$
– RubiksmooseFeb 7 at 20:30

\$\begingroup\$A material component that the spell consumes can't be replaced by a component pouch or a focus.\$\endgroup\$
– r256Feb 7 at 20:30

1

\$\begingroup\$@r256 it does not say the casting consumes it, you might form a circle with it, but if you don't do so, it is not consumed\$\endgroup\$
– AndrásFeb 7 at 20:32